86610-16-4Relevant academic research and scientific papers
Organoboranes. 40. A simple preparation of borinic esters from organolithium reagents and selected boronic esters
Brown, Herbert C.,Cole, Thomas E.,Srebnik, Morris
, p. 1788 - 1792 (2008/10/08)
Monoorganyldiisopropoxyboranes, RB(O-i-Pr)2, react cleanly at -78 °C with 1 equiv of organolithium compounds, R′Li, to form the corresponding complexes of the borinic acid esters, LiRR′B(O-i-Pr)2. Treatment of these complexes with an equivalent of anhydrous hydrogen chloride in ethyl ether liberates the borinic esters, RR′BO-i-Pr, and isopropyl alcohol, usually readily separated by distillation. Alternatively, treatment of the complexes with 1 mol of an appropriate acid chloride liberates the borinic esters, RR′BO-i-Pr, and an isopropyl ester, RCO2-i-Pr. By careful selection of the acid chloride, these two products can be easily separated by distillation. A careful examination of the reaction of other boronic esters in this reaction revealed that the boronic esters of 1,3-propanediol forms the 1:1 complex cleanly on reaction with organolithium compounds at -78 °C. (Formula Presented) Treatment of these ate complexes either with hydrogen chloride in ether or with an appropriate acid chloride provides the pure borinic ester. Consequently, simple rational procedures are now available for the synthesis in high purities and yields of either boronic or borinic acids and esters, either through hydroboration or through the use of organolithium compounds.
Organoboranes. 31. A simple preparation of boronic esters from organolithium reagents and selected trialkoxyboranes
Brown, Herbert C.,Cole, Thomas E.
, p. 1316 - 1319 (2008/10/08)
The reaction of methyllithium with trimethoxyborane at -78°C in ethyl ether yields a mixture of methylated boranes and their corresponding ate complexes. We have found that under the same conditions triisopropoxyborane reacts cleanly with methyllithium to form the lithium methyltriisopropoxyborate complex. Protonation of this complex with anhydrous hydrogen chloride quantitatively yields methyl diisopropoxyborane. This reaction of organolithium reagent with triisopropoxyborane appears to provide a general, valuable route to boronic esters. Other alkoxyboranes were examined for their selectivity for monomethylation by methyllithium. In addition to triisopropoxyborane, triisobutoxyborane and tri-sec-butoxyborane also give the methylboronic esters quantitatively. This development provides the first general preparation of boronic esters from organolithium reagents.
Autoxidation von Trialkylboranen, II. 1H-NMR-Spektroskopische Untersuchungen zum Mechanismus der Redoxreaktion zwischen Trialkylboranen und Dialkyl(alkylperoxy)boranen
Huschens, Rainer,Rensch, Rainer,Friebolin, Horst
, p. 3581 - 3588 (2007/10/02)
The intermolecular redox reaction between dimethyl(methylperoxy)borane and 9>trimethylborane, triethylborane, tri-n-propylborane, triisopropylborane, and tri-n-butylborane, as well as between 9>dimethyl(methylperoxy)borane and trimethylborane was investigated directly in an NMR spectrometer.From the CIDNP effects a mechanism of this redox reaction was deduced, which can be considered as generally valid for any reaction between (alkylperoxy)boranes and alkylboranes.According to this mechanism, the alkoxy group of the peroxide is transferred to the boron atom of the alkylborane after homolysis of the O-O bond.The four-coordinate boron compound eliminates instantly an alkyl radical, which forms a radical pair in the singlet state with the boroxyle radical left after the homolysis of the peroxide.
